Blackboard or slate



A. B. ELLIS.

BLACKBQARD 0R SLATE. APPLICATION FILED JuLY a0. 1920.

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.ALLAN rB; ELLIS, OF APPLETON, WISCONSIN.

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1 Application filed July To all whom t may concern:

Be it known that I, ALLAN B. ELLrs, a citizen ,of the United States ofAmerica, residing at Appleton, in the county of. Outagamie and State ofWisconsin, have invented certain new'and useful Improvements 1nBlackboards or Slates, of which the following is a specification.

This invention relates to new and useful improvements in blackboards andslates and has for its primary object to provide a novel construction ofdevice wherein parallel lines equi-distantly spaced may be drawn uponthe board in khorizontal and vertical directions to provide block spacesfor purposes' of enlarging drawings or pictures.

A further object of the inventionis to provide a blackboard or slatedevice combined with a novel type of ruler,.the frame o of the deviceand the ruler having coperating parts to hold the ruler rigidlypositioned during the act of drawing a line, these cooperating devicescarried by "the frame being so positioned to..permit the drawing of aline at each side edge of the rulerV with all of the linesequi-distantly positioned.

With the above and other objects in view,

`the present invention consists in the novel form, combination andarrangement of parts hereinafter more fully described in connection withthev accompanying drawings, wherein like reference characters indicatesimilar parts throughout the several views. f

In the drawings,

Figure 1 is a top plan view of a blackboard or slate constructed inaccordance with the present invention, with the coperating ruleroperatively arranged thereon,

Fig. 2 1s a cross sectional view takenon lline II-II of Fig. l showingthe pins at the end of the ruler received in the openings in the frameof the device, and

Fig. 3 is a perspective view of the ruler.

Briefly described, the present invention aims to provide a novelV formof blackboard or slate which will be hereinafter referred to as ablackboard embodying a rectangular frame having an ordinary writingplate section carried thereby. The side faces of the frame strips areprovided with `openings extending therethrough and arranged equaldistances apart. A lnovel type of ruler is associated with theblackboardY and embodies an intermediate section that engagesSpecification of Letters Patent.` n Paten-.ted Allg, V165` 1921,

ao, ieee. serial No. 400,161.

the writing plate of the blackboard with the loweredge facesl thereofcut away to provide clearance spaces for the side frames ofV thevblackboard and to overlie the same wlile pins are carried by the endsof the ru er openings in the blackboard frame. The ruler is of a widthequal to one-half the distance between two adjacentopenings so that whenthe pins centrally depending from the ends of the ruler are received inan opening, a line may be drawn at each straight side edge thereof sothat upon a change of position of the ruler with the drawing ofsubsequentlines, all of the lines will be equi-distantlyspaced. In asimilar manner, the ruler is positioned vertically upon the blackboardand cross lines may be drawn as desired. Y Referringmore in detail tothe laccompanying drawing, therey is illustrated a blackboard ofrectangular formation emn bodying side strips at the meeting endsthereof and secured together in any suitable manner. As shown in Fig. 2,the lower inner edge of each strip 4 is grooved as at 6 to provide apocket for the rectangular writing plate member 7 that may beadhesively, frictionally, or otherwise secured therein.V As shown inFig. l, the side `strips 4 are provided with equi distantly vspacedalined openings 8 eX- tending therethrough, the corresponding openingsat the opposed sides of the blackboard being alined and parallel withthe two other opposite side strips.

The type of ruler employed with this blackboard isshown in detail inFigs. 2 and 8, the same embodying an elongated body l portion 9,rectangular Vin shape and having opposite straight edges 9. The lowerfaces of the opposite ends of the ruler 9 are cut away asat 10 to permitthe lower face of the ruler 9 to engage .the upper surface of thevwriting plate 7 as shown in Fig. 2, the

ruler being cut away for a distance inwardlyof each end to permit theinner walls 10 of the cut away portions to substantiallyT fric` tionallyengage the inner edges of the side strips 4 and when so positioned, theupper walls -of the cut away portions engage the upper sides ofthestrips 4. A headed pin l1 depends from each end of the ruler 9 at thecutaway portion thereof'and a cap plate .l2 is mounted upon 'the upperSide of each Vend of the ruler to overlie the headof the 4 having miterjoints 5' pin as shown in Fig. 2 to retain the same in position. Thepins 11 are carried bythe ruler 9 in oppositely alined strip openings 8as shown in said gure.

From the above detailed description of the device, it is believed thatthe construction and operation thereof will at once be apparent, itbeing noted that the ruler 9 is of a width equal to onehalf the distancebetween the two adjacent openings 8 so that when the pins 1l arereceived in alined openings at opposite sides of the blackboard frame, aline may be drawn at each straight edge 9 of the ruler and upon placingthe ruler in the next transversely alined pair of openings, the ruler ispositioned whereby two additional lines may be drawn so that four lineswith two applications of the ruler are arranged equal distances apartand in parallelism.

In a similar manner, vertical lines may be drawn and with the blockarrangement of lines on the writing plate or board 7 the enlargement orreduction of pictures and the like may be accomplished in an obviousmanner, Also, with the pin and opening connection between the blackboardand ruler, a positive grip between the two elements is provided so thatslipping of the ruler will be entirely eliminated and wearing of theengaging parts practically eliminated in view of the pin entering thehole.

While there is herein shown and described the preferred embodiment ofthe invention, it is nevertheless to be understood that minor changesmay be made therein without departing from the spirit and scope of theinvention as hereinafter claimed.

What is claimed as new is:

The combination with a blackboard having a rectangular frame andequi-distantly spaced openings extending through the frame midway theedges at each side thereof, of a ruler having the opposite ends thereofcut away upon the lower face to provide inner side shoulderssubstantially frictionally engaging the inneredges of the opposite sidesof` the blackboard frame, the upper walls of the cut away portionsoverlying the upper sides of the frame, and a pin depending from the endof the ruler into the cut away portion selectively received intransversely alined openings, the ruler being of a. width equal'to halfthe distance between two adjacent openings wherebytwo parallel lines maybe `drawn at each mounting of the ruler with all of the linesequi-,distantly spaced.

In testimony whereof I affix myV signature.

ALLAN B ELLIS.

